Die attach systems, and methods of attaching a die to a substrate

ABSTRACT

A die attach system is provided. The die attach system includes: a support structure for supporting a substrate; a die supply source including a plurality of die for attaching to the substrate; a bond head for bonding a die from the die supply source to the substrate, the bond head including a bond tool for contacting the die during a transfer from the die supply source to the substrate; a first motion system for moving the bond head along a first axis; and a second motion system, independent of the first motion system, for moving the bond tool along the first axis.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.62/726,387, filed Sep. 3, 2018, the content of which is incorporatedherein by reference.

FIELD

The invention relates to systems and methods for attaching a die tosubstrate, and more particularly, to improved systems and methods ofattaching a die to a substrate without picking of the die from a diesupply source.

BACKGROUND

In connection with the placement of a die on a substrate (e.g., theplacement of a semiconductor die on a substrate), many conventionalapplications utilize a “pick and place” operation. In such operations, adie is “picked” from a semiconductor wafer or other die supply source,and then the die is moved to (and “placed” on) a target substrate. Suchoperations may also utilize one or more transfers between a “pick” tooland a “place” tool.

Certain die attach applications do not utilize a pick and placeoperation. For example, a die supply source (e.g., a wafer including aplurality of die) may be positioned between a bond tool and a substrate.Die included in the die supply source may be attached to a film or thelike. After alignment between the bond tool, the die to be attached, anda placement location of the substrate—the bond tool presses the dieagainst the placement location of the substrate. Adhesive on a lowersurface of the die (and/or on the placement location of the substrate)is provided such that the die is now secured to the substrate. Such bondtools may include a plurality of pins (e.g., vertically actuatable pins)for contacting the die in connection with a transfer from the die supplysource to the substrate.

Complications tend to exist in connection with such applications(applications that do not utilize a pick and place operation). Forexample, because the changing alignment of the multiple elements (e.g.,the bond tool, the die to be attached, and the placement location of thesubstrate), the speed of the die attach operation, and the associatedUPH (i.e., units per hour processed), may be compromised.

Thus, it would be desirable to provide improved systems and methods forattaching a die to a substrate, particularly in connection withapplications that do not utilize a pick and place operation.

SUMMARY

According to an exemplary embodiment of the invention, a die attachsystem is provided. The die attach system includes: a support structurefor supporting a substrate; a die supply source including a plurality ofdie for attaching to the substrate; a bond head for bonding a die fromthe die supply source to the substrate, the bond head including a bondtool for contacting the die during a transfer from the die supply sourceto the substrate; a first motion system for moving the bond head along afirst axis; and a second motion system, independent of the first motionsystem, for moving the bond tool along the first axis.

According to another exemplary embodiment of the invention, a die attachsystem is provided. The die attach system includes: a support structurefor supporting a substrate; a die supply source including a plurality ofdie for attaching to the substrate; a bond head for bonding a die fromthe die supply source to the substrate, the bond head including a bondtool for contacting the die during a transfer from the die supply sourceto the substrate; a first motion system for moving the die supply sourcealong a first axis; and a second motion system, independent of the firstmotion system, for moving the die supply source along the first axis.

According to yet another exemplary embodiment of the invention, a methodof attaching a die to a substrate is provided. The method includes thesteps of: (a) operating a first motion system for moving a bond headalong a first axis, the bond head for bonding the die from a die supplysource to the substrate, the bond head including a bond tool forcontacting the die during a transfer from the die supply source to thesubstrate; (b) operating a second motion system, independent of thefirst motion system, for moving the bond tool along the first axis; and(c) transferring the die from the die supply source to the substratethrough operation of the bond tool.

According to yet another exemplary embodiment of the invention, anothermethod of attaching a die to a substrate is provided. The methodincludes the steps of: (a) operating a first motion system for moving adie supply source along a first axis; (b) operating a second motionsystem, independent of the first motion system, for moving the diesupply source along the first axis; and (c) transferring the die fromthe die supply source to the substrate through operation of a bond tool,the bond tool being included as part of a bond head, the bond tool forcontacting the die during transfer from the die supply source to thesubstrate.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is best understood from the following detailed descriptionwhen read in connection with the accompanying drawings. It is emphasizedthat, according to common practice, the various features of the drawingsare not to scale. On the contrary, the dimensions of the variousfeatures are arbitrarily expanded or reduced for clarity.

FIG. 1A is a block diagram top view of elements of a die attach systemin accordance with an exemplary embodiment of the present invention;

FIG. 1B is another block diagram top view of elements of the die attachsystem of FIG. 1A;

FIG. 1C is a block diagram side view of elements of the die attachsystem of FIG. 1A;

FIG. 1D is a detailed view of an example bond tool of the die attachsystem of FIG. 1A in accordance with an exemplary embodiment of thepresent invention;

FIGS. 2A-2E are block diagram side views illustrating a die attachoperation of the die attach system of FIG. 1A in accordance with anexemplary embodiment of the present invention; and

FIGS. 3A-3C are block diagram side views illustrating a die attachoperation of the die attach system of FIG. 1A in accordance with anotherexemplary embodiment of the present invention.

DETAILED DESCRIPTION

As used herein, the term “die” is intended to refer to any structureincluding (or configured to include at a later step) a semiconductorchip or die. Exemplary “die” elements include a bare semiconductor dieincluding a bare LED semiconductor die, a semiconductor die on asubstrate (e.g., a leadframe, a PCB, a carrier, a semiconductor chip, asemiconductor wafer, a BGA substrate, a semiconductor element, etc.), apackaged semiconductor device, a flip chip semiconductor device, a dieembedded in a substrate, amongst others.

According to certain exemplary embodiments of the present invention, dieattach systems are provided that include an inventive device forsupporting a bond head or a die supply source. Such a device includes(i) a long stroke part which supports a short stroke axis, and (ii) theshort stoke part which supports the bond head or the die supply source.For example, the long stroke axis may travel at a constant velocity,relative to the substrate (configured to receive the die in the dieattach/bond sequence), during the bond sequence. The short stroke axisstops, relative to the substrate, during the bond action. After the bondaction the short stroke axis catches up with the long stroke axis andmoves to the next bond position.

Exemplary elements included in the inventive device include thefollowing combinations: (1) a short-long stroke bond head with arelative slow single axis die supply source, using a method of skippingdies on the source to prevent that the slower supply source axis limitsthe bond rate; (2) a short-long stroke bond head with short-long strokedie supply source; and (3) an alternative fast bond device (e.g. laser,air pulse) with short-long stroke die supply source. Of course, otherdevices (and associated methods of operation) are contemplated.

Aspects of the invention relate to combining the advantages of a longstroke axis and a short stroke axis (in connection with either, or both,of the bond head and the die supply source). In certain examples appliedto the bond head, the short stroke part of the motion axis enables highbond rates, while the long stroke part enables the bond head to reachthe desired stroke. Exemplary ranges of motion for the short strokeinclude (i) less than 1 mm, (ii) less than 3 mm, or any desired range ofmotion.

FIG. 1A illustrates die attach system 100. Die attach system 100includes a support structure 110 for supporting a substrate 112, a diesupply source 108 including a plurality of die 108 a configured to beattached to substrate 112, and a bond head 104 including a bond tool 104b for contacting die 108 a during a transfer of die 108 a from diesupply source 108 to substrate 112. Die attach system 100 also include abond head support 102 and a supply support 106. Bond head support 102and supply support 106 are each mounted on machine structure 150 suchthat bond head support 102 and supply support 106 are independentlymoveable relative to machine structure 150. Bond head support 102supports moveable bond head 104. Bond head 104 includes a camera 104 a(and other visions system components) for use in connection withalignment and/or inspection operations. Die supply source 108 ismoveably mounted on supply support 106. In the exemplary embodiment ofthe invention shown in FIG. 1A (and in FIGS. 1B-1C), during a die attachoperation, die supply source 108 is positioned between bond tool 104 band substrate 112 supported by support structure 110.

FIG. 1B illustates bond head 104 (including camera 104 a and bond tool104 b) positioned over die 108 a which, in turn, is positioned oversubstrate 112. FIG. 1C is a cross-section view of FIG. 1B along line1C-1C and illustrates bond head 104 with camera 104 a and bond tool 104b positioned over substrate 112. Two “bonded” die 108 a′ have beenbonded to substrate 112 at respective bonding locations and bond tool104 b is shown engaging another die 108 a above a third respectivebonding location on substrate 112.

FIG. 1D illustrates a block diagram of an example of bond tool 104 b.More specifically, bond tool 104 b may include at least one pin 104 b 1for contacting die 108 a in connection with a transfer from die supplysource 108 to substrate 112. Further, as shown in FIG. 1D, bond tool 104b may include a plurality of pins 104 b 1 for contacting die 108 a inconnection with a transfer from die supply source 108 to substrate 112.Each of the plurality of pins 104 b 1 may be separably, or collectively,moveable (e.g., along a vertical axis) with respect to the remainder ofbond tool 104 b to transfer die 108 a to substrate 112.

Of course, bond tool 104 b including one or more pins 104 b 1 (as shownin FIG. 1D) is an example of bond tool 104 b. In other embodiments ofthe invention, bond tool 104 b may not include pins 104 b 1, but maytransfer die 108 a witout pins 104 b 1.

In accordance with certain exemplary embodiments of the invention, atleast one of (i) bond tool 104 b, and (ii) die supply source 108, ismoved along an axis (e.g., a horizontal axis, or a substantiallyhorizontal axis) using a first motion system and a second motion system.For example: FIGS. 2A-2E illustrates a first motion system 102′ and asecond motion system 104′ (the operation of which is detailed below inconnection with FIGS. 2A-2E); and FIGS. 3A-3C illustrate a first motionsystem 106′ and a second motion system 108′ (the operation of which isdetailed below in connection with FIGS. 3A-3C). It will be appreciatedthat die attach system 100 as illustrated and described herein mayinclude (i) a first motion system and a second motion system for movingbond tool 104 b (as in FIGS. 2A-2E), (ii) a first motion system and asecond motion system for moving die supply source 108 (as in FIGS.3A-3C), or both (i) and (ii).

FIG. 2A illustrates a side sectional view of die attach system 100(previously described in connection with FIGS. 1A-1C), but now bond head104 includes a first moveable carrier 114 and a second moveable carrier116. First moveable carrier 114 is positioned between bond head support102 and second moveable carrier 116. Second moveable carrier 116 ispositioned between first moveable carrier 114 and bond tool 104 b. Firstmotion system 102′ provides for linear motion along a first axis (thex-axis in FIG. 2A, but another linear axis, such as the y-axis, iscontemplated) of first moveable carrier 114 with respect to bond headsupport 102. Second motion system 104′ provides for linear motion alongthe first axis of second moveable carrier 116 with respect to firstmoveable carrier 114. Also shown in FIG. 2A is motion system 106′configured for moving die supply source 108 with respect to supplysupport 106. Each of motion systems 102′, 104′, and 106′ includeselements (not specifically shown for simplicity) between their adjacentcomponents. For example, motion system 102′ includes motion systemelements (e.g., motors, slides, ball screws, bearings, etc.) to providemotion between first moveable carrier 114 with respect to bond headsupport 102.

Exemplary first motion system 102′ is included in a gantry system of dieattach system 100 for carrying bond head 104. Die 108 a are positionedabove, and will be bonded to, bonding locations 112 a on substrate 112.Generally, bond head 104 will move in the vertical (e.g., z-axis)direction of the double headed arrow while bonding die 108 a to bondinglocations 112 a, in turn.

FIG. 2B illustrates movement of bond head 104 along bond head support102 with first motion system 102′, while bond tool 104 b engagesleftmost die 108 a and bonds leftmost die 108 a to leftmost bondinglocation 112 a. As bond head 104 moves to the right in FIG. 2B, bondtool 104 b, using second motion system 104′, moves left relative tofirst moveable carrier 114 to stay above leftmost bonding location 112a, and bond leftmost die 108 a to leftmost bonding location 112 a.

FIG. 2C illustrates the further rightward movement of bond head 104along bond head support 102 using first motion system 102′, while bondtool 104 b stays above leftmost bonding location 112 a by moving furtherleftward relative to first moveable carrier 114 using second motionsystem 104′, with bond tool 104 b moving upward to its pre-bondingposition within second moveable carrier 116.

FIG. 2D illustrates the continued rightward movement of bond head 104along bond head support 102 using first motion system 102′, while bondtool 104 b now move rightward relative to first moveable carrier 114using second motion system 104′ so as to now position bond tool 104 babove next bonding location 112 a in anticipation of the next bonding.Die supply source 108 (e.g., a wafer, such as an LED wafer or other LEDdie source), using third motion system 106′, moves to the left relativeto supply support 106.

FIG. 2E illustrates movement of die supply source 108, using motionsystem 106′, to the right relative to substrate 112 so that theremaining leftmost die 108 a is now above next bonding location 112 a,and beneath bond tool 104 b. The process continues similar to FIGS.2A-2E to bond leftmost die 108 a to next bonding location 112 a, and tothen reset to bond the then next remaining leftmost die 108 a (or otherdie 108 a, as desired) to the then next bonding locaton 112 a.

FIG. 3A illustrates a further embodiment of the invention wherein thereis a single motion system 102′ for bond head 104 (including a moveablecarrier). In FIG. 3A (and FIGS. 3B-3C), supply support 106 (forsupporting die supply source 108) includes support 118, first motionsystem 106′, moveable carrier 120 (for carrying die supply source 108,which may be a wafer, such as an LED wafer or other LED die source), andat least a portion of second motion system 108′. Bond tool 104 b (shownas vertical dashed line below bond head 104) is positioned aboveleftmost bonding die 108 a and leftmost bonding location 112 a.

First motion system 106′ provides for linear motion along a first axis(the x-axis in FIG. 3A, but another linear axis, such as the y-axis, iscontemplated) of moveable carrier 120 with respect to support 118.Second motion system 108′ provides for linear motion of die supplysource 108 along the first axis with respect to moveable carrier 120.Each of motion systems 102′, 106′, and 108′ includes elements (notspecifically shown for simplicity) between their adjacent components.For example, motion system 106′ includes motion system elements (e.g.,motors, slides, ball screws, bearings, etc.) to provide motion betweenmoveable carrier 120 and support 118.

FIG. 3B illustrates bonding of leftmost bonding die 108 a to leftmostbonding location 112 a as moveable carrier 120 moves rightward and diesupply source 108 moves leftward relative to moveable carrier 120, andremains stationary relative to the bond tool as a bond is formed betweenleftmost bonding die 108 a and leftmost bonding location 112 a.

FIG. 3C illustrates post-first-bond and the movement of bond head 104 tothe right to position the bond tool over next bonding location 112 awhile fourth moveable carrier 120 moves rightward with die supply source108 also moveing rightward to align the bond tool over the now leftmostbonding die 108 a on die supply source 108 over next bonding location112 a. The process continues similar to FIGS. 3A-3C for the next bond.

As shown in the various drawings, a double headed arrow intends to referto motion (or potential motion through a motion system) of the relevantelement.

Exemplary embodiments of the invention tend to result in a substantiallyhigher bond rates without accuracy loss.

While not expressly shown in the drawings, the invention contemplatesembodiments where each of the bond head and the die supply sourceincludes multiple motion systems. For example, die attach systems withinthe scope of the invention may include first and second motion systemsfor moving a bond tool (such as in FIGS. 2A-2E), along with first andsecond motion systems for moving a die supply source (such as in FIGS.3A-3C).

While the invention has been described primarily with respect to dieattach operations where there is no “pick” operation, it is not limitedthereto. The invention has broad applicability in the semiconductorbonding industry including die attach machines (sometimes referred to asdie bonders) or other packaging machines (e.g., flip chipmachines/operations, advanced packaging operations, etc.).

Although the invention has been described and illustrated with respectto the exemplary embodiments thereof, it should be understood by thoseskilled in the art that the foregoing and various other changes,omissions and additions may be made therein and thereto, without partingfrom the spirit and scope of the present invention. Rather, variousmodifications may be made in the details within the scope and range ofequivalents of the claims and without departing from the invention.

What is claimed:
 1. A die attach system comprising: a support structurefor supporting a substrate; a die supply source including a plurality ofdie for attaching to the substrate; a bond head for bonding a die fromthe die supply source to the substrate, the bond head including a bondtool for contacting the die supply source during transfer of the diefrom the die supply source to the substrate; a first motion system formoving the bond head including the bond tool along a first axis; and asecond motion system, independent of the first motion system, for movingthe bond tool along the first axis.
 2. The die attach system of claim 1wherein the bond tool includes at least one pin for contacting the diesupply source in connection with a transfer of the die from the diesupply source to the substrate.
 3. The die attach system of claim 1wherein the bond tool includes a plurality of pins for contacting thedie supply source in connection with a transfer of the die from the diesupply source to the substrate.
 4. The die attach system of claim 1wherein the die supply source includes an LED wafer, and the pluralityof die are a plurality of LED die.
 5. The die attach system of claim 1wherein at least one of (i) the die, and (ii) a bonding location of thesubstrate configured to receive the die, includes adhesive for securingthe die to the bonding location after the transfer from the die supplysource to the substrate.
 6. The die attach system of claim 1 wherein thefirst motion system is included in a gantry system of the die attachsystem for carrying the bond head.
 7. The die attach system of claim 1wherein the first axis is an x-axis or a y-axis of the die attachsystem.
 8. The die attach system of claim 1 wherein during movement ofthe bond head in a first direction along the first axis, the secondmotion system selectively moves the bond tool in a second directionalong the first axis, the second direction being opposite of the firstdirection.
 9. The die attach system of claim 1 wherein the die supplysource is configured to be positioned between the substrate and the bondtool during a bonding operation.
 10. A method of attaching a die to asubstrate, the method comprising the steps of: (a) operating a firstmotion system for moving a bond head including a bond tool along a firstaxis, the bond head for bonding the die from a die supply source to thesubstrate, the bond tool for contacting the die supply source during atransfer of the die from the die supply source to the substrate; (b)operating a second motion system, independent of the first motionsystem, for moving the bond tool along the first axis; and (c)transferring the die from the die supply source to the substrate throughcontact of the bond tool with the die supply source.
 11. The method ofclaim 10 wherein the bond tool includes at least one pin for contactingthe die supply source in connection with the transfer of the die fromthe die supply source to the substrate in step (c).